6-Ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene

ABSTRACT

New spiranic compound, viz. 6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene, its preparation and use of same as perfume or flavor-modifying ingredient.

SUMMARY OF THE INVENTION

The invention relates to a compound of formula ##STR1##

The invention also relates to a process for the preparation of thecompound defined hereinabove, which comprises

(A) reacting 2-ethyl-6,6-dimethyl-cyclohexanone with but-1-yn-3-ol inthe presence of a strong base or with an organo-metallic derivative offormula ##STR2## wherein symbol ME represents an alkali metal or ahalogenomagnesium radical and R represents a trialkyl-silyl,tetrahydropyranyl, tert-butyl, 3-oxa-pent-2-yl, 3-oxa-but-2-yl or aMg-halogen radical, hydrolyzing the thus obtained reaction product andfinally treating the hydrolization product with an acidic reagent; or

(B) reacting 2-ethyl-6,6-dimethyl-cyclohex-2-en-1-one with anorganometallic derivative of formula (II) as defined hereinabove,hydrolyzing the thus obtained reaction product, hydrogenating thehydrolization product and finally treating the obtained hydrogenationproduct with an acidic reagent.

The invention also relates to a process for improving, enhancing ormodifying the flavour properties of artificial flavours, foodstuffs,beverages, pharmaceutical preparations or tobacco products, or the odourproperties of perfumes, perfume bases, perfume compositions or perfumedproducts, which comprises adding thereto a small but effective amount ofthe compound of formula (I) defined hereinabove.

The invention more specifically relates to a process for imparting ablack-currant type odour free from sulfury tonality to perfumes, perfumebases, perfume compositions or perfumed products, which comprises addingthereto a small but effective amount of the compound of formula (I)defined hereinabove.

The invention finally relates to a perfume or flavour-modifyingcomposition, which comprises the compound of formula (I) definedhereinabove as organoleptically active ingredient.

BACKGROUND OF THE INVENTION

The fruity odour note typical of black-currant is particularly wellappreciated in modern perfumery. Up to now however it could not beeasily reproduced by making use of prior known ingredients,black-currant buds absolute e.g.: this expensive fragrant material ofnatural origin possesses in fact a rather complex odour wherein thetypical fruity note is often associated with undesired tonalities. Inthe same context, one can cite synthetic compounds such as2,6,9,10,10-pentamethyl-1-oxa-spiro[4.5]deca-3,6-diene and2,6,9,10-tetramethyl-1-oxa-spiro[4.5]deca-3,6-diene, of formulae##STR3## respectively, known in the art as possessing a fresh, green andnatural odour reminiscent of that of mint leaves, clary sage andblack-currant, as well as a fruity flavour more or less reminiscent ofthat of citrus fruits, grape-fruit more particularly [see DE-OS No.2,634,077 and DE-OS No. 2,749,511, respectively].

Menthone-thiol-8 of formula ##STR4## also develops a fruity odour ofblack-currant type, which odour is however associated with a sulfurytonality [see DE-PS No. 2,008,254]. Menthone-thiol-8 moreover is oflimited interest in perfumery in view of its lack of stability in soaps,shampoos and detergents.

Contrary to the teaching of the art, the compound of formula (I), viz.6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene possesses a"clean" fruity note of black-currant type, namely free from any sulfurytonality. In view of its stability in soaps, detergents or house-houldmaterials, it can be moreover more widely used in perfumery than theprior known analogous odoriferous ingredients.

In the field of perfumery, compound (I) is characterized by an originalodour note of black-currant type, free from sulfury tonality,reminiscent of the fruity note of black-currant buds absolute. It can beadded to a great number of perfume compositions of different types suchas fruity, fresh, minty, flowery, rosy, woody or chypre compositionse.g., wherein it efficiently develops its typical black-currant note.

In order to achieve such an original olfactive effect, compound (I) canadvantegously be used as unique fragrant ingredient, for example in theform of solution in conventional solvents such as ethyl alcohol, diethylphthalate, dipropylene-glycol or ethyl citrate e.g., or in admixturewith the perfuming ingredients commonly used in the art, in that case inthe form of a perfume base e.g. Compound (I) is appreciated in fineperfumery as well as in the preparation of perfumed products such assoaps, detergents, shampoos, cosmetics or house-hold materials, e.g.

The olfactive effects which can be achieved by making use of compound(I) greatly depend on the concentration, the nature of the fragrantcoingredients or the nature of the material to which it is added. Forthe preparation of perfume compositions e.g., interesting effects can beachieved by using proportions as low as 0.05% of the weight of thecomposition. Characteristic olfactive effects are generally obtained byusing compound (I) in proportions comprised between about 0.1 and 5%.Higher proportions, 20% or even more of the weight of the perfumecomposition can also be used, especially when particular odoriferouseffects are desired.

In the field of flavours, compound (I) is characterized by its typicalfruity and woody taste, reminiscent of that of black-currant. The saidcompound can thus be used for preparing artificial fruity flavours suchas black-currant, raspberry or other red berries flavours, wherein itadvantageously develops a fresh, fruity and woody flavour note,reinforcing at the same time the natural aspect of such flavourcompositions.

Compound (I) can also be used for flavouring foodstuffs, beverages,pharmaceutical preparations or tobacco products. Flavouring effects suchas those described hereinabove can be achieved by using the saidcompound in proportions comprised between about 0.01 and 10 ppm (partsper million), preferably between about 0.1 and 5 ppm of the weight ofthe thus flavoured material. Proportions superior to 10 ppm can also beconsidered, especially when particular flavouring effects are desired.

According to the process of the invention (method A)2-ethyl-6,6-dimethyl-cyclohexanone can be first reacted withbut-1-yn-3-ol, in the presence of a strong base. Suitable strong basesare mineral organic bases such as potassium hydroxide, butyl-lithium,potassium tert-butoxide or sodium or lithium amide e.g. Although thisdoes not represent a necessary condition for achieving high yields offinal product, the said reaction can be effected in the presence ofinert organic solvents: in this case ethers, aliphatic or aromatichydrocarbons or mixtures of same are preferred. The said reaction ismoreover carried out at a temperature generally comprised between about25° and 55° C., preferably of the order of 35° C.

After subsequent hydrolysis there is isolated a novel intermediatecompound having the formula ##STR5## which is subsequently subjected toan acidic treatment. The said acidic treatment is effected by means of astrong mineral or organic acid, preferably in an aqueous organic medium.Suitable organic solvents are those defined in the preceeding reactionstep; suitable strong acids are formic, phosphoric, sulfuric,polyphosphoric, benzenesulfonic or p-toluenesulfonic acids e.g. or evenan acidic diatomaceous earth. The said acidic treatment is preferablyeffected at a temperature comprised between about 50° and 100° C., moregenerally at the boiling temperature of the reaction mixture.

According to another embodiment of the process of the invention (methodA) compound (I) can also be obtained from2-ethyl-6,6-dimethyl-cyclohexanone, by reacting the same with anorgano-metallic derivative of formula ##STR6## as previously defined,hydrolysis and subsequent acidic treatment of the hydrolization product.In this case, the same reaction conditions as those applied hereinabovecan advantageously be used.

According to a further embodiment of the process of the invention(method B), 2-ethyl-6,6-dimethyl-cyclohex-2-en-1one can be reacted withan organo-metallic derivative of formula (II) as defined hereinabove, inthe conditions of a Grignard reaction. After subsequent hydrolysis thereis isolated a novel intermediate compound having the formula. ##STR7##wherein R is different from Mg-halogen. The said intermediate compoundis then subjected to hydrogenation, in the presence of a metal catalystsuch a Raney nickel or in the presence of a partially inactivatedcatalyst, Lindlar catalyst e.g. There is thus obtained a further novelintermediate compound of formula ##STR8## wherein R is different fromMg-halogen, which is finally subjected to an acidic treatment to affordcompound (I). The said acidic treatment can be effected in the sameconditions as those applied for the compound of formula (III).

As obtained from the above described syntheses, compound (I) may existin the form of a mixture of stereoisomers A and B (see hereinafter)##STR9## or in the form of one of the above stereoisomers. Formula (I)as defined in the invention is deemed to represent either singlestereoisomers or mixtures of same. For practical and economical reasonshowever, compound (I) is used in accordance with the invention asdirectly obtained from the described process.

The invention will be illustrated in a more detailed manner by thefollowing examples wherein the temperatures are given in degreescentigrade.

EXAMPLE 1 Preparation of6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene

Method A

(i) 448 g (8 mole) of KOH and 1100 ml of di-isopropyl-ether were firstintroduced into a reaction vessel fitted with cooling and stirringdevices. 154 g (2.2 mole) of but-1-yn-3-ol were then added to the abovemixture (temperature 25°-30°; addition period:30 min), followed by 308 g(2.0 mole) of 2-ethyl-6,6-dimethyl-cyclohexanone (addition period:30min; dropwise). The reaction mixture was then stirred at 35° for 17hours and, after cooling, 500 ml of water were progressively addedthereto. After separation of the organic phase, washing with 5% aqueousH₂ SO₄ (200 ml), drying over Na₂ SO₄, concentration and finaldistillation, there were isolated a first portion of unreacted2-ethyl-6,6-dimethyl-cyclohexanone (46 g) and 313 g (78% yield) of2-ethyl-6,6-dimethyl-1-hydroxyl-1-(3-hydroxy-but-1-yn-1-yl)-cyclohexane.

An analytical sample was purified by cristallization in cyclohexane,m.p. 136°.

IR: 3600, 2390, 1210, 1035, 920 cm⁻¹ ;

NMR: 1.00 (3H, t, J=7 Hz); 1.00 and 1.09 (6H, 2s); 1.48 (3H, d, J=7 Hz);1.0-1.9 (9H, m); 1.97 (2H, broad s); 4.59 (1H, q, J=7 Hz)δ ppm;

MS: m/e=206 (7), 188 (63), 173 (76), 162 (26), 147 (100), 131 (47), 117(54), 105 (67), 91 (79), 82 (83), 69 (58), 55 (79), 43 (88), 41 (94), 29(62).

(ii) 100 g (0.45 mole) of the above compound in admixture with 175 g of86% H₃ PO₄ and 200 ml of tetrahydrofuran were heated to reflux for 20hours. After cooling and addition of 100 ml of petrol ether (50/70), thereaction mixture was successively washed with water, then with 5%aqueous NaHCO₃, dried over Na₂ SO₄, evaporated and finally subjected tofractional distillation to afford 31 g (34%) of the desired compound,b.p. 90°/2 Torr.

According to the vapour phase chromatography analysis (siliconcolumn-UCON; 120°-180°), the thus prepared compound consists in a 1:1mixture of stereoisomers.

IR: 1450, 1375, 1360, 1355, 1345, 1110, 1075, 1045, 1030, 1000, 970,940, 910, 860, 830, 800, 745, 710 cm⁻¹ ;

NMR: 0.85 and 0.87 (2×1.5H, 2s); 0.93 (3H, s); 0.98 (3H, t, J=7 Hz);1.30 (3H, d, J=6 Hz); 1.4-1.7 (2H, m); 1.7-2.2 (4H, m); 4.9 (1H, m);5.38 and 5.49 (2×0.5H, 2m); 5.58 (1H, d×d, J₁ =6 Hz, J₂ =2 Hz); 5.77 and5.84 (2×0.5H, d×d, J₁ =6 Hz, J₂ =1 Hz)δ ppm;

MS: m/e=150 (100), 135 (28), 121 (52), 107 (6), 91 (7), 79 (18), 67 (2),55 (4), 43 (18), 29 (3).

2-Ethyl-6,6-dimethyl-cyclohexanone used hereinabove as starting materialwas prepared as follows: 600 g (3.95 mole) of2-ethyl-6,6-dimethyl-cyclohex-2-en-1-one [prepared fromn-propyl-isopropyl-ketone and acrolein; see DE-OS No. 2,547,223] werehydrogenated at room temperature and at atmospheric pressure, in thepresence of 15 g of 5% palladium on charcoal. After consumption of 93 lof H₂ and filtration, there were isolated 601 g (99% yield) of thedesired compound, b.p. 76°/12 Torr.

IR: 1705, 1450, 1380, 1365, 1130, 1035, 990 cm⁻¹ ;

MS: M⁺ =154 (20); m/e=126 (6), 82 (100), 69 (31), 56 (38), 55 (33), 41(32), 27 (9).

Method B

(i) 6.0 g (0.042 mole) of 3-(3-oxa-pent-2-yloxy)-but-1-yne were addeddropwise and under nitrogen atmosphere to a mixture of 14 g (0.042 mole)of 40% ethylmagnesium bromide in ether and 7.5 ml of anhydrous ether(addition period:30 min-temperature:20°). After having been heated toreflux for 1 hour, the reaction mixture was cooled to 20° and 3.8 g(0.025 mole) of 2-ethyl-6,6-dimethyl-cyclohex-2-ene-1-one were addedthereto. The reaction mixture was stirred for 1 further hour, thencooled to 0°-5° and successively treated with 5 ml of water and 15 ml of5% H₂ SO₄ in water. After extraction with ether, washing, drying (Na₂SO₄) and evaporation of the organic layer, there were isolated 7.7 g ofcrude residue. Distillation thereof (150°/0.1 Torr) gave 4.4 g (59%yield) of a compound of formula ##STR10## which was characterized asfollows:

NMR: signals at 1.0-2.6; 3.3-4.0; 4.2-5.1; 5.3-5.6δ ppm;

MS: m/e=232 (17), 217 (11), 204 (26), 192 (39), 175 (15), 163 (26), 148(85), 133 (96), 120 (47), 105 (80), 91 (40), 73 (59), 55 (34), 45 (100),43 (91), 29 (40).

(ii) 2.9 g (0.01 mole) of the above compound in 20 ml of ethyl acetatewere hydrogenated at room temperature, under atmospheric pressure, inthe presence of 0.5 g of Lindlar catalyst (H₂ consumption:280 ml). Afterfiltration and evaporation, there were isolated 2.9 g (99% yield) of acompound having the formula ##STR11## A sample thereof was purified foranalysis (distillation:110°/2 Torr).

IR: 3610, 3450, 1700, 1655, 1460, 1380, 1150-1020 cm⁻¹ ;

NMR: 0.8-1.7 (20H); 1.9-2.3 (4H, m); 2.8 and 2.9 (1H, 2s); 3.2-3.9 (2H,m); 4.6-5.7 (5H, m)δ ppm;

MS: M⁺ =206 (13); m/e=194 (13), 177 (9), 163 (5), 150 (58), 135 (25),121 (48), 107 (22), 93 (16), 79 (12), 73 (46), 55 (28), 45 (67), 43(100), 31 (68).

(iii) 1.0 g (3.4 mmole) of the above compound in 5 ml of petrol ether

(80/100) were heated to reflux for 5 hours, under nitrogen atmosphere,in the presence of 4 g of 30% H₂ SO₄ in water. After washing of theorganic layer with an aqueous solution of NaHCO₃, drying over Na₂ SO₄,evaporation and distillation, there were isolated 0.6 g (86% yield) ofthe desired title compound.

The thus obtained compound was found identical with that preparedaccording to method A above.

EXAMPLE 2

A perfume base composition was prepared as follows:

    ______________________________________                                        Ingredients           Parts by weight                                         ______________________________________                                        IRALIA®.sup.1     160                                                     Vetiveryl acetate     100                                                     Benzyl salicylate     100                                                     Santalol              80                                                      Phenylethyl alcohol   80                                                      CYCLOSIA®.sup.1   80                                                      Musk ketone           70                                                      Bergamot oil          60                                                      Jasmin absolute, Morocco                                                                            60                                                      Rose of may absolute  40                                                      Synthetic civette tincture                                                                          40                                                      Synthetic Tonkin musk tincture                                                                      30                                                      EXALTOLIDE®.sup.1 30                                                      Eugenol               30                                                      Rose oil, Bulgary     15                                                      Undecylenic aldehyde 10%*                                                                           15                                                      Total                 990                                                     ______________________________________                                         *in diethyl phthalate                                                         .sup.1 origin: FIRMENICH SA, GenevaSwitzerland                           

The addition of 1 g of6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene to 99 g of theabove base imparts thereto a fresh and fruity lifting odour, reminiscentof that of black-currant buds. The thus perfumed base compositiondevelops a fuller and more pleasant odour than that of the originalbase.

EXAMPLE 3

A base perfume composition was prepared as follows:

    ______________________________________                                        Ingredients           Parts by weight                                         ______________________________________                                        Cetronellol           200                                                     Benzyl benzoate       100                                                     α-Amyl-cinnamic aldehyde                                                                      80                                                      Hydroxy-citronellol   80                                                      Ylang-ylang oil       60                                                      Phenylethyl alcohol   60                                                      HEDIONE®.sup.1    40                                                      Phenoxyethyl propionate                                                                             30                                                      α-Damascone 1%* 20                                                      Linalol               20                                                      Geranylacetone        10                                                      Total                 700                                                     ______________________________________                                         *in diethyl phthalate                                                         .sup.1 origin: FIRMENICH SA, GenevaSwitzerland                           

The thus prepared perfume base is characterized by a generic floweryodour.

The addition of 300 g of6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]-deca-3,6-diene to 700 g ofthe above base imparts thereto a typical fruity note of black-curranttype. The thus obtained "black-currant" perfume composition may beharmoniously combined with many other perfume compositions, of varioustypes.

EXAMPLE 4

100 mg of 6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene wereincorporated into 100 g of commercial soap having a neutral odour. Thethus perfumed paste was then used for the manufacture of toilet soapbars which were finally subjected to olfactive evaluation. It was notedthat the perfumed soap bars developed a pleasant fruity odour ofblack-currant type.

EXAMPLE 5

A black-currant syrup--prepared from 1 part of concentrated commercialsyrup and 9 parts of water--was flavoured with6-ethyl-2,10,10-trimethyl-1-oxa-spiro[4.5]deca-3,6-diene, at a rate of 5ppm.

After comparison with an unflavoured (control) diluted syrup, it wasnoted that the flavoured syrup possessed a fuller, rounder and morenatural taste together with a typical fruity and woody note.

What I claim is:
 1. Compound of formula ##STR12##